1. Field of the Invention
The present invention relates to a terminal device comprising a terminal base formed on a bobbin for an exciting coil for operating a contact of an electromagnetic contactor or the like, and a terminal plate fixedly connected to the terminal base.
2. Description of the Prior Art
A conventional terminal device of this type is shown in FIGS. 8 and 9. Terminal plate 22 is fixedly connected to terminal base 31 formed on bobbin 21. Terminal plate 22 comprises a rectangular electrically-conductive plate having one end portion bent perpendicularly to provide bent portion 17. Upwardly-directed projection 17a is formed on the end or edge of bent portion 17, and horizontally-projecting tongue 9, around which a wire of an exciting coil is wound, is formed on and protrudes outwardly from the end of bent portion 17. As shown in FIG. 9, terminal base 31 to which terminal plate 22 is fixedly connected has L-shaped groove 31d into which terminal plate 22 is inserted in a direction of the plane thereof. Terminal base 31 also has hole 31a which engages projection 17a when terminal plate 22 is inserted into L-shaped groove 31d. Terminal plate 22, when inserted into groove 31d, is retained by terminal base 31 so that terminal plate 22 is immovable upward and downward, right and left, and back and forth. Side wall 31c of terminal base 31 is abutted against a side of terminal plate 22 when terminal plate 22 is fully inserted into L-shaped groove 31d of terminal base 31, thereby positioning terminal plate 22. Side wall 31c also serves to effect an intimate engagement of projection 17a in hole 31a.
The problems with the terminal device of the above construction are as follows. Namely, as is well known, a wire having a very small diameter is used as an exciting coil winding of an electromagnetic contactor or the like, wherein the exciting coil winding is connected to terminal plate 22 by winding one end portion of the exciting coil winding around tongue 9. In addition, an external conductor is connected to terminal plate 22 by threading terminal screw 3 into screw hole 22a of terminal plate 22. During this threading operation, however, a large force is applied to terminal plate 22, and if the distance between bent portion 17 of terminal plate 22 and screw hole 22a is long, a large bending moment acts on the bent portion 17. As a result, tongue 9 on which the end portion of the exciting coil winding is wound moves thus causing a risk that the end portion of the exciting coil winding may be cut.